Rotary adsorption assembly

ABSTRACT

An apparatus for adsorptive filtering of contaminants from a gaseous stream is provided. The apparatus includes a frame member. The frame includes a base member which is rotatable about an axis. A plurality of walls are attached to the base member and extend axially therefrom to a top member for providing a plurality of circumferential segment areas. The walls include a radially inner side for defining an axially extending inner chamber and a radially outer side for defining an outer periphery. A plurality of adsorption elements, each having an axial first side and an axial second side, are axially spaced in each of said circumferential segment areas. A duct or the like radially directs contaminated air into at least an entire one of the segment areas. The apparatus has a duct arrangement for directing a substantially radial flow of air into at least one of said segments from the outer periphery through the axial first side of each of said adsorption elements in generally an axial direction through the adsorption element to exit the axial second side and into said axially extending inner chamber for exhausting decontaminated air out through the axial chamber. 
     The present invention may also include a regenerative portion which can regenerate the adsorptive elements during operation of the apparatus. The regenerative portion includes ducts for supplying a heated regenerative air stream and a cooling air stream to strip contaminants from the adsorptive elements and then cool them to a suitable adsorptive temperature.

This is a continuation of U.S. patent application Ser. No. 547,988,filed Jul. 3, 1990, now U.S. Pat. No. 5,057,128.

BACKGROUND OF THE INVENTION

The present invention relates to a filtration apparatus for filteringgaseous contaminants out of an air stream. More specifically, thepresent invention relates to a rotary adsorption apparatus for filteringof volatile constituents from a gaseous stream.

In recent times, it has become necessary for many industries to providemethods of removing and/or reducing contaminants from a gaseous airstream. Thus, many air purification systems have been produced forremoving or purifying of various gaseous contaminants.

A gaseous stream which is in need of purification is produced duringoperation of a manufacturing procedure or other job function. Forinstance, volatile constituents are commonly produced, in paint spraybooths, during paint spraying operations. It is necessary to removethese volatile constituents prior to exhaustion of the air in the paintbooth to the atmosphere. It is desirable to provide a purificationsystem which can remain operational for extended periods of time, suchthat it does not substantially interfere with production operations.Such a purification apparatus would allow continued operation of theplant or the like without frequent and costly shutdown times forreplacement or regenerating of the apparatus.

Adsorptive media, such as activated carbon and the like, has been usedfor some time to remove volatile constituents from a gaseous stream.These types of apparatuses have the advantage that the filtrationelement can be regenerated to produce added life to the apparatus. U.S.Pat. Nos. 4,778,422 to Dawson and 4,402,717 to Izumo et al. disclosesuch adsorptive filtering devices U.S. Pat. No. 4,778,422 to Dawsonshows an adsorption apparatus which is rotatably mounted such that theadsorption medium can be regenerated at the same time a gaseous streamis being purified U.S. Pat. No. 4,402,717 to Izumo et al. discloses asimilar apparatus that provides an axially directional flow ofcontaminated gas through a portion of an elongated cylindricaladsorption element, such that a portion of the adsorptive element may beregenerated during filtration of a gaseous stream.

While these patents have disclosed improvements in the art, there stillremains the need to replace adsorptive elements when the adsorptiveelements can no longer be regenerated. This requires replacement of anentire specifically designed adsorptive cartridge prior to continuingpurification of the gaseous stream. Additionally, the volume occupied bythese structures tends to be prohibitively large in light of the finalvolume flow of air treated.

In many of these prior structures it is necessary to provide apre-filter sacrificial carbon bed which will take out high boiling pointcontaminants which may tend to load up the regeneratable bed, thuslessening its useful life. The necessity of such an external sacrificialbed adds greatly to the volume of the final assembly.

Thus, it is a goal in the art to provide replaceable adsorptionelements, which can be readily and easily replaced when necessary. Ithas also been a goal in the art to reduce or eliminate the pre-filteringsacrificial bed to reduce space consumed by an adsorption apparatus.Additionally, it has been a goal in the art to provide an apparatuswhich will have improved airflow characteristics at lower total occupiedvolumes and be readily adaptable to existing duct work in paint spraybooths and the like. It has also been a goal in the art to provide amore efficient method of removing volatile constituents from a gaseousstream without the disadvantages set forth above.

SUMMARY OF THE INVENTION

In accordance with the present invention, an apparatus for adsorptiveremoval of contaminants from a gaseous stream is provided. The apparatusincludes a frame member. The frame member includes a base member whichis rotatable about an axis. A plurality of walls are attached to thebase member and extend axially therefrom to a top member for providing aplurality of circumferential segment areas. The walls include a radiallyinner side for defining an axially extending inner chamber and aradially outer side for defining an outer periphery.

A plurality of adsorption elements, each having an axial first side andan axial second side, are axially spaced in each of said circumferentialsegment areas.

A duct or the like radially directs contaminated air into at least anentire one of the segment areas.

The apparatus has a duct arrangement for directing a substantiallyradial flow of air into at least one of said segments from the outerperiphery through the axial first side of each of said adsorptionelements in generally an axial direction through the adsorption elementto exit the axial second side and into said axially extending innerchamber for exhausting decontaminated air out through the axial chamber.

The present invention may also include a regenerative portion which canregenerate the adsorptive elements during operation and rotation of theapparatus.

Thus, in accordance with the present invention, an improved adsorptiondevice is provided wherein adsorptive elements are readily replaceableas individually needed and which provides continual regeneration of theadsorptive elements until they can no longer be regenerated.Additionally, the present invention provides an efficient space savingdevice which is readily adaptable existing duct work for reducingvolatile constituents from a gaseous stream.

Additional benefits and advantages of the present invention will bereadily appreciated when taken in conjunction with the description ofthe preferred embodiment, the brief description of the drawings and theclaims, as set forth below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view partially broken away showing the rotaryadsorption apparatus of the present invention in its operationalenvironment;

FIG. 2 is a detailed sectional view of the apparatus of FIG. 1;

FIG. 3 is a sectional view taken along line 3--3 of FIG. 2;

FIG. 4 is a detailed view showing the sealing configuration at theregenerative duct portion; and

FIG. 5 is a detailed view showing an alternate embodiment of a sealingconfiguration at the regenerative duct portion.

DESCRIPTION OF A PREFERRED EMBODIMENT

In accordance with the present invention, there is provided anapparatus, generally shown at 10, for adsorptive filtering ofcontaminants of a gaseous stream. The apparatus includes a frame means,generally indicated at 12, for supporting a plurality of adsorptionelements 14. The frame means includes a base member, generally indicatedat 16, which is rotatable about an axis 18. A wall means, generallyindicated at 20, is attached to the base member 16, and extends axiallytherefrom for providing a plurality of circumferential segment areas 22,as best seen inFIG. 2. The wall means 20 includes a radially inner side,generally indicated at 24, for defining an axially extending innerchamber 26. The wall means 20 also includes an outer peripheral side fordefining an outerperiphery, generally indicated by 28. Preferably, thewall means 20 includes a plurality of upstanding walls 30, which extendaxially upwardlyfrom the base member 16 and extend in a radial directionalong the base member 16 to define the segment areas 22.

A plurality of the adsorption elements 14 are axially spaced in each ofthesegment areas 22. Each of the adsorption elements includes a firstaxial side 32 and a second axial side 34. The adsorption elements 14 aregenerally of a "pie slice" shape and are permeable only in generally anaxial direction from the first axial side through an adsorption mediumto the second axial side 34. The adsorption elements contain anadsorption medium, such as an activated carbon or the like, foradsorptively trappingvolatile constituents.

In a preferred embodiment, the adsorptive elements 14 are removablysecuredin the segments 22 by the provision of transversely extendingledges 53 provided on the walls 30 and at the location of eachadsorptive element. Thus, each adsorptive element may be individuallyremoved and replaced with a fresh element as required.

In a preferred embodiment, the adsorptive elements include a sacrificialupper portion 14a, which may be readily disposed of, and a lower carboncassette 14b which can be replenished or replaced separately.

The sacrificial upper portion is provided directly in the mainadsorptive unit. This provides for the elimination of a separatesacrificial bed unitrequired in the prior art which was providedupstream from the unit. Thus, the present invention reduces spacepreviously required for housing the sacrificial bed. The beneficialremoval of high boiling point (about 300° F.-400° F.) volatileconstituents is substantially accomplished by the sacrificial portion14a prior to the gaseous stream reaching the more expensiveregeneratable carbon cassette 14b. Preferably,the portion 14a is filledwith a disposable inexpensive granulated type activated carbon whereasthe portion 14b is a honeycomb like material withan activated carbonattached on the walls of the honeycomb, as is known to those skilled inthe art.

A means, such as an exhaust duct work 36 from a paint booth or othervolatile containing source, radially directs contaminated air into atleast one of the segment areas 22. The duct work may be provided bywalls 36 for forming a chamber for directing air to a plurality of thesegments.

Referring in particular to FIG. 3, a first duct means is provided, suchas indicated generally at 40, for directing the substantially radialflow of volatile constituents containing air into at least one of thesegment areas 22 from the outer peripheral side 28 through the axialfirst side 32of the adsorption elements, and thereafter in an axialdirection to exit the axial second side 34 of the adsorption element forexhaust through theaxially extending inner chamber 26.

In a preferred embodiment, the duct means 40 includes horizontallyslanted walls 42 and 44 which enclose the entire portion of the segmentalong its radial length, and an axially extending inner wall 41 forenclosing the radially inner portion of the segment. The walls 42 and 44slope from the outer periphery downward to the inner periphery. Thewalls 42 and 44, the upper portion 58 and base 16 provide air inputports 43 and air output ports 45 between each of the spaced adsorptiveelements 14, as best seen in FIG. 3.

A regenerative duct means, generally shown at 46, is provided in theaxially extending inner chamber 26. The regenerative duct means 46 iscommunicative with at least an inner portion of one of the segment areas22 for forcing of a regenerative gaseous stream through the second axialside 44 and out through the first axial side and then outward forstorage for disposal, reuse or destruction of the volatile constituents.As shown in the drawings, in a preferred embodiment the regenerativeduct means includes a first duct portion 46b for regeneration of one ormore areas containing adsorptive elements at a time. A second ductportion 46a is provided for sending a cooling stream through thepreviously regenerated adsorptive elements for returning the elements tothe proper temperature for continued adsorption.

Regenerative duct means 46 includes an input manifold 48 and an outputmanifold 50. As stated above, the walls 42 and 44 provide respectiveinputports 43 and output ports 45, which are situated between theadsorptive elements 14. The input manifold is sealingly coupled with theinner periphery of at least one of the segments 22, for allowing aregenerative gaseous stream to be passed through the ports 45 andthrough the adsorptive elements 14. The output manifold includesportions for forming ports 54 which sealingly engage the ports 43 suchthat the regenerative stream exiting the first axial side 32 exitsthrough the manifold 50 by way of the output ports 54, which couple withthe ports 43 for removing the regenerative gas stream therefrom.

Referring now to FIG. 4, lip seals 51 are attached to the walls 30 whichcooperate with the flanges 55a and 55 for sealing between the chambers46aand 46b and the walls 30 during regeneration of the adsorptiveelements 14.Lip seals 57 are attached and extended radially outwardlyfrom the walls 30for sealing between flanges 50a and the individualwalls 30 forming the segments. Alternatively, the sealing lips could beprovided on the flanges55, 55a or 50a such as shown for example bysealing lip 59 shown in phantomin FIG. 4.

Referring now to FIG. 5, there is shown an alternate embodiment of asealing arrangement for the chambers 46a or 46b. In this embodiment thewalls 30 include a circumferentially extending wall 61 for forming afirst `T` shaped flange. The chambers 46a or 46b include `T` flanges 63.A pair of lip seals 65 are provided on the circumferential outer edge ofthe flanges 61 which seal against flanges 63. This configuration allowsonly one segment to be subjected to regenerative or cooling gases at atime during rotation of the assembly. Thus, because of thisconfiguration the flanges 63 either engage the adjacent pairs of sealinglips 61 or a particular flange may engage one of each of contiguouspairs of sealing lips such that either a regenerative or cooling streampasses through onlyone of the segments or is stopped by the flange 61.Of course, the lip seals could be provided on the flanges 63 instead ofthe flange 61 to accomplish the same result.

In operation, referring now to FIGS. 1 and 3, the gas purification flowof the gaseous stream is illustrated in solid arrows and theregenerative gaseous flow is illustrated with dashed arrows. The gaspurification flow includes the input of volatile contaminated airthrough the duct 36 or 38 which flows into the ports 43. Thereafter,because of the enclosure of theadsorptive element by side wall 30, innerwalls 41 and the slanted walls 42and 44, in conjunction with the topportion 58 and the base 16, an air flowpath is created wherein the airmay flow through the adsorption elements 14in a segment 22 or pluralityof segments 22 in a general axial direction and out through the ports45. The air exits ports 45 into axial chamber 26and thereafter to theatmosphere or back into the booth as a purified gas. During thisprocess, the cylinder may be rotated, as shown by arrows 56, by way of asuitable motor 59, such that different adsorptive elements 14 aresequentially utilized. Alternatively, the frame could be rotatedstepwise one segment at a time to provide the rotation movement Therotation of the frame is preferably rotated at about 1 revolution perhourto 4 revolutions per hour, such that the volatiles adsorbed will notexceedthe capacity of the adsorption media prior to regeneration. In apreferred embodiment the motor 59 is a 1760 RPM motor which is coupledto RPM reduction apparatus or drive means such that the shaft outputfrom the reducer to the frame is in the above range. This prevents anyoverloading of the adsorptive elements which would allow volatile vaporsto load up and desorb with the gaseous stream exiting from chamber 26.

During this rotation, the regeneration of the adsorptive elements mayalso be accomplished as follows. First, a regenerative gas, such asheated steam or the like, is introduced into the manifold portion 46b.The regenerative gas stream flows through the ports 45 causing thegaseous stream to flow axially upward through the adsorptive elements 14from side34 to side 32 and out the port 43 to the output manifold 50.Preferably, the regenerative gas is drawn through the manifold 46b andelements 14 under a negative pressure to reduce the possibility ofcontaminated air re-entering the chamber 26. The resulting stream iscollected for removal and destruction of volatile constituents strippedfrom the adsorption medium contained in elements 14. Because, theadsorptive elements are heated during the regenerative process it isnecessary to cool the elements back to a suitable temperature whereadsorption can occur. In order to accomplish this, a fan (not shown) maybe utilized to direct purified air from chamber 26 through the chamber46a through the adsorptive elements 14 from channel 45 out throughchannel 43 and to exhaust into the chamber formed by walls 36. Ifdesired, a cooling or refrigeration apparatus may be provided to coolthe air stream prior to entering the adsorptive elements. Thereafter,the particular adsorptive elements 14 in a segment 22 may be circulatedfor further purification functions by the rotation of the frame 12.

Thus, with both the purification and regeneration operations takingplace at once the apparatus of the present invention can be continuallyremovingvolatile constituents of gas while at the same time regeneratingthe adsorptive elements such that when a regenerative adsorptive elementcontinues through the process it will again be used for removingvolatile constituents as its rotation comes into the duct work 36. Therotation cancontinue until the adsorptive elements 14 become unusablewhereafter they can be easily replaced by sliding them out and replacingthem with new elements, as may be required.

Suitable doors or other access is provided on the duct work forproviding access for replacement of the adsorptive elements. Theconfiguration of the present invention provides improved airdistribution and air velocity through the adsorption elements andbetween the individual elements. Additionally, the adsorption elementsare readily replaceable when necessary and a net reduction in volume isrealized in the present invention.

While the above description constitutes the preferred embodiment of thepresent invention it is to be appreciated that the invention issusceptible to modification, variation and change without departing fromthe proper scope and fair meaning of the accompanying claims.

What is claimed is:
 1. A method for regenerating an adsorption apparatusincluding adsorption elements having an adsorbent contaminated withvolatile contaminants prior to placing the adsorptive element back inservice comprising the steps of:(a) providing an apparatus foradsorptive filtering of contaminants from a gaseous stream, saidapparatus including: a frame means for supporting a plurality ofadsorption elements, said frame means including a base member rotatableabout an axis, a wall means attached to said base member and upstandingaxially therefrom for providing a plurality of circumferential segmentareas, said wall means including a radially inner side for defining anaxially extending inner chamber and a radially outer side for definingan outer periphery, a plurality of adsorption elements axially spaced ineach of said circumferential segment areas, each of said plurality ofadsorption elements having an axial first side and an axial second side;and a duct means for directing said substantially radial flow of airbetween contiguous adsorption elements into at least one of said segmentareas through the axial side of each of said adsorption elements to exitthe axial second side for exhausting of decontaminated air; wherein saidbase member is rotatable; (b) passing the heated gaseous stream throughat least one of said circumferential areas for heating the adsorbent ofsaid plurality of adsorption elements therein to de-adsorb volatileconstituents thereby removing volatile constituents from said pluralityof adsorption elements; and (c) immediately thereafter passing a coolinggaseous stream through at least one of said circumferential areas forcooling of the adsorbent of said plurality of adsorption elements tooperational temperatures prior to placing the plurality of adsorptionelements back in service for adsorptive purification of gaseous stream.2. The process of claim 1 further comprising rotating a frame includingthe adsorptive element for causing the adsorptive element to come intocontact with the heated gaseous stream and thereafter rotating the frameinto position for causing said adsorptive element to come into contactwith the cooling gaseous stream.
 3. The process of claim 1 furthercomprising passing the heated and cooling gaseous stream through theadsorptive elements in a direction opposite to a previous flow of acontaminated gaseous stream through the elements.
 4. An apparatus foradsorptive filtering of contaminants from a gaseous stream, saidapparatus comprising:a frame means for supporting a plurality ofadsorption elements, said frame means including a base member rotatableabout an axis, a wall means attached to said base member and upstandingaxially therefrom for providing a plurality of circumferential segmentareas, said wall means including a radially inner side for defining anaxially extending inner chamber and a radially outer side for definingan outer periphery; a plurality of adsorption elements axially spaced ineach of said circumferential segment areas, each of said plurality ofadsorption elements having an axial first side and an axial second side;a means for radially directing contaminated air into at least one ofsaid circumferential segment areas; and a first duct means for directingsaid substantially radial flow of air between contiguous adsorptiveelements into at least one of said segment areas through the axial firstside of each of said adsorption elements to exit the axial second sidefor exhausting of decontaminated air; wherein said base member isrotatable for sequentially interposing segment areas into the radiallydirected contaminated air for continual adsorptive purification of saidgaseous stream.
 5. The apparatus of claim 4 wherein each of saidadsorptive elements includes a sacrificial first portion adjacent thefirst axial side for removal of high boiling point volatile constituentsfrom the gaseous stream and a regeneratable second portion adjacent thesecond axial side for removing volatile constituents from the gaseousstream.
 6. The apparatus of claim 4 wherein each of said adsorptiveelements includes a sacrificial first portion and a regeneratable secondportion.
 7. The apparatus of claim 4 wherein said adsorptive elementsare pie slice shaped.
 8. The apparatus of claim 4 further comprising:asecond duct means communicative with at least one of said segments forcausing a regenerative gaseous stream to progress through the secondaxial side of each of said adsorptive elements and out through the firstaxial side; and a means for providing a regenerative gaseous stream tosaid duct means for regenerating at least one of said segmentscontaining said adsorptive elements in a circumferential segment areaduring rotation of said frame means.
 9. The apparatus of claim 8 whereineach of said adsorptive elements is individually removable from saidsegment areas.
 10. The apparatus of claim 8 wherein each of saidadsorptive elements includes a sacrificial first portion adjacent thefirst axial side for removal of high boiling point volatile constituentsfrom the gaseous stream and a regeneratable second portion adjacent thesecond axial side for removing volatile constituents from the gaseousstream.
 11. The apparatus of claim 8 wherein each of said adsorptiveelements includes a sacrificial first portion and a rejuvenatable secondportion.
 12. The apparatus of claim 8 wherein said second duct meansfurther comprises a first duct portion for directing a first heatedgaseous stream through each of said adsorptive elements in at least oneof said segments and a second duct portion for directing a coolinggaseous stream through each of said adsorptive elements in at least oneof said segments for cooling of said adsorptive elements to an effectiveadsorption temperature.
 13. The apparatus of claim 12 wherein said firstduct portion is communicative with a plurality of said segment areas forregenerating the adsorption elements in a plurality of the areas. 14.The apparatus of claim 12 further comprising a means for cooling of thecooling gaseous stream to a temperature below ambient temperature priorto passing the cooling gases through the adsorption elements.
 15. Theapparatus of claim 4 wherein each of said adsorptive elements isindividually removable from said segment areas.
 16. The apparatus ofclaim 15 wherein said adsorptive elements are pie slice shaped.